Anomalous Origin of the Three Major Coronary Arteries from a Single Common Ostium

ABSTRACT: The prevalence of coronary anomalies is about 1.3% among patients who undergo coronary angiography.¹ Although the majority of coronary artery anomalies are incidental findings and are not clinically significant, the interarterial course between the great vessels of the aberrant artery may be responsible for syncope, angina, arrhythmias or sudden death.² There are only a few case reports in the literature that describe the origin of all coronary arteries from a single ostium. This type of anomaly has been seen in only 0.024–0.044% of the population.³ This is a first case where not only was there a common ostium of the left anterior descending artery and right coronary artery without a left main, but an absent left circumflex artery with blood supply of its territory by a posterolateral/marginal branch from the right posterior descending artery and conal branch. J INVASIVE CARDIOL 2010;22:499–501 ————————————————————————————— Case description. A 60-year old female with a history of hypertension, diabetes, hyperlipidemia and obesity was referred for an exercise stress test after complaining of atypical chest pain. No ischemic changes were noted after 6 minutes of exercise on the electrocardiogram, but she had a small anterior defect on myocardial perfusion imaging (MPI). The patient subsequently underwent cardiac catheterization, which revealed anomalous coronary arteries that were otherwise angiographically normal. There was a common ostium of the left anterior descending artery (LAD) and right coronary artery (RCA). There was no left main artery. The left circumflex artery was absent, but its territory filled from the conus branch and from the large posterolateral/marginal branches that originated from the right posterior descending artery (PDA). An Amplatz (AL1) catheter was used to engage the common ostium and all three vessels were visualized with a single injection. The patient’s left ventricular function was normal (Figures 1 and 2). The patient was subsequently referred for cardiac computed tomography angiography (CTA) to delineate the course of the LAD and rule out its compression between the great vessels. Cardiac CTA demonstrated an anterior trajectory of the LAD between the ascending aorta and the right ventricular outflow tract, with an intramyocardial portion (bridge). The obtuse marginal and posterolateral branches filled from the right PDA through a large intramyocardial segment, as well as from a conal branch coursing anteriorly to the pulmonary artery (Figures 3, 4 and 5). There was mild coronary atherosclerosis with focal calcifications in the proximal, mid and distal RCA but without significant stenosis. Despite the lack of obstructive coronary disease on cardiac catheterization and CTA, MPI showed a small anterior myocardial perfusion defect, most likely related to the anomalous origin of the LAD and the presence of a large mid-LAD bridge. In a pathological analysis that reviewed anomalous coronary arteries arising from the contralateral sinus of Valsalva and having an interarterial course between the great vessels, age > 30 years was the only variable associated with a decreased incidence of sudden cardiac death. Our patient’s anomalies were probably lower risk since the course was intramyocardial rather than interarterial and the patient exceeded the typical age of risk for sudden death.⁴ Although a myocardial bridge is the most common congenital coronary anomaly with a widely varied incidence (0.5–2.5% on coronary angiographic studies; 15–85% at autopsy), malignant arrhythmias, myocardial infarction and sudden cardiac death can very rarely be attributed to it.⁵ A prospective study of 59 patients between 45 and 66 years of age who had an isolated LAD myocardial bridge resulting in > 70% systolic compression on an angiogram and otherwise normal or nonobstructive coronary disease had a very good prognosis when they were followed with medical therapy. While the majority of the patients did experience atypical chest pain, there were no deaths, new acute coronary syndromes, congestive heart failure or hospitalizations related to a cardiac cause over a mean follow-up period of 37 ± 13 months.⁶ Currently, stenting of the myocardial segment is not recommended due to the high rate of elastic recoil. A high-risk procedure such as surgical myectomy requiring a deep incision to relieve the compression of the vessel is also not optimal and is advised to patients with refractory angina despite medical therapy.6 Coronary artery bypass grafting is limited by concerns about long-term graft patency in the absence of a fixed obstruction of the native artery,7 although internal mammary artery anastomosis to the LAD may be the treatment of choice in patients with unsuccessful coronary stenting, in-stent restenosis or with significant coronary disease.⁸ In the absence of coronary atherosclerosis and a pathological interarterial course, this patient was considered a good candidate for medical management. She had no evidence of systolic compression of the LAD on cardiac catheterization, and the risk of surgery was judged to outweigh the benefit. She was advised to continue coronary artery disease risk-factor modification including weight reduction, blood pressure, diabetes and lipid control. At the 6-month follow-up office visit, she is asymptomatic on beta-blocker therapy.

References

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————————————————————————————— From The Zena and Michael A. Weiner Cardiovascular Institute, Mount Sinai School of Medicine, New York, New York. The authors report no conflicts of interest regarding the content herein. Manuscript submitted February 16, 2010, provisional acceptance given March 11, 2010, final version accepted April 13, 2010. Address for correspondence: Biana Trost, MD, Mount Sinai School of Medicine, Mount Sinai Services at Elmhurst Hospital Center, Mount Sinai School of Medicine, 79-01 Broadway, Room D3-87, Elmhurst, NY 11373. E-mail: biana.trost@mssm.edu